In many surgical and medical procedures, a lavage unit is employed to deliver fluid to a particular location on or in the body of a person receiving medical attention. For example, during orthopedic surgery, a lavage unit may be employed to deliver pressurized pulses of water or saline solution to an exposed surface of the bone in order to clean the bone. There are also some non-surgical procedures performed which likewise make it desirable to apply pulses of water to a specific site on an individual's skin. Thus, if an individual is suffering from some type of bed sore or some other type of skin wound, it is a common practice to use a lavage unit to clean the wound prior to applying a dressing to the wound.
A common type of medical/surgical lavage unit includes a handpiece to which a tip assembly is selectively attached. Often, inside the handpiece is a small pump that periodically delivers a quantity of pressurized fluid. Alternatively, the pressurized fluid is delivered to the handpiece from an external pump. The fluid is discharged through a discharge tube integral with the tip assembly to the selected site on or in the patient. These lavage units deliver fluid in pressurized pulses for two reasons. One reason is that fluid pulses quickly strike the site to which they are applied and leave the site; this action serves to foster the desirable removal of debris from the site. Secondly, the discrete fluid pulses do not obstruct the view of the site as much as it can be obstructed when exposed to a continuous flow of pressurized fluid.
Most lavage units, in addition to having a conduit through which the sterile fluid is discharged, have a conduit through which the discharged fluid is removed from the site to which it is applied. Typically, the fluid is initially withdrawn from the site through a suction tube, also part of the tip assembly. The fluid, as well as any debris in the fluid stream, then flow through a conduit integral with the handpiece. The handpiece suction conduit is connected to a second suction tube that is connected to a suction system separate from the irrigator. Thus, given their ability to essentially simultaneously clean a site on a patient and remove the debris generated by the cleaning process, it should be readily apparent why irrigators have become useful tools for facilitating many medical and surgical procedures.
Further, it is the common practice to manufacture both the handpiece and tip assembly of lavage unit as use-once items. One reason these units are use-once is economics. The cost of forming these devices out of sterilizable components and then sterilizing the devices after each use can be greater than the cost of providing a quantity of use-once device. A second reason these units are use-once items is related to weight. The weights of components forming a handpiece manufactured to be sterilizable are greater than the weights of comparable components forming a use-once handpiece. During a procedure, such as bone cleaning, it may be necessary to hold the lavage unit steady for time periods that run into the minutes. Making the lavage unit as light as possible reduces the muscle fatigue of the individual required to hold the unit steady for an extended periods of time.
Applicant's U.S. Pat. No. 6,022,329 and U.S. Pat. No. 7,153,287, both of which are explicitly incorporated herein by reference, disclose use-once lavage units. In these patents and in other publications, lavage units are sometimes referred to as irrigators.
The lavage units of the incorporated by reference patents work reasonably well. Still, sometimes with these lavage units, as well as other lavage units the suction tubes integral with the tip assemblies clog with debris. This means use of the unit has to be interrupted in order to either clear the clog or to attach a replacement tip assembly. Taking the time to perform either of these procedures runs contrary to the goal of modern medical practice, that a procedure should be performed as quickly as possible so as to minimize the time the patient is both held under anesthesia or has internal body tissue that is exposed to the ambient environment.
Further as with any product, there is always a desire to hold the costs of product to a minimum. One area in which this has affected lavage handpiece design is the trigger. The trigger is the manual member the practitioner depresses to selectively actuate the pump motor. In some situations, the practitioner may want to rapidly control the on/off discharging of the lavage fluid by the pump. When this type of control is required, the trigger needs to operate as a momentary contact switch. In some situations the practitioner may want the pump to remain on for an extended period of time, 30 seconds or more. If the trigger is of the momentary contact variety, the practitioner has to exert mental and physical effort ensuring the trigger remains in the on state, the trigger should operate as a switch that is selectively toggled on and off. This is a reason why it would be useful to provide a lavage unit with a toggle switch that is toggled between the on and off states. However, sometimes, in same procedure the practitioner may want the trigger to function as both as momentary contact switch on one phase of the procedure and, in another phase of the procedure, as a toggle switch. To date it has proven difficult to provide a use-once lavage handpiece with a trigger that can operate both as a contact switch and a toggle switch.